You didn't actually present this take so I take responsibility for how I interpreted it, but...

Why does it seem like this is presented as a bad take? What's wrong with ecological changes and corrections taking centuries, or longer?

Too often I see environmental advocates wringing their hands over changes which absent humanity would be just a chance for other subsystems to adapt or related ecology to evolve while the initial system rebuilds itself.

Just because humanity "depends" upon the later results or effects of these processes (or just because humanity caused them) doesn't mean any anything, really.

Consider from the environment's perspective:

This, too, shall pass.

The rate of change.

There's a climate science "gotcha" which is that the Earth's average temperature has been much higher in the past than it is now. No one disputes this. The problem is not so much the absolute level as the rate of change, which gives less time for everything to adapt.

Bingo. Rapid temperature changes of only a few degrees can become mass extinction events. Of course, the natural world has eventually recovered from every mass extinction - but it can take millions of years to get back to the same level of biodiversity as before the extinction.

Thank you, this gives me some perspective regarding humanity's effect. I won't claim to understand it all, or agree/disagree with it, but it definitely helps me account for scale.

And also who is profiting from causing these changes which harm other people.

Perhaps some people dislike the fact that in many cases these quaint "ecological changes and corrections" that "would be just a chance for other subsystems to adapt or related ecology to evolve" also just so happen to be cases of a very small group of people profiting immensely from the inconvenience, suffering, and death of very large groups of people.

Hearing that very small group of people (or researchers and political advocates funded by that very small group of people) paint a quaint picture of humans as one tiny part of Gaia might make some people uncomfortable.

It’s pretty bad news for the creatures and plants in that ecosystem. Maybe in evolutionary terms it’s not a big deal, but it will mean the wiping out many populations and even species.

At a personal level, the extinction of the giant sequoias or the spotted owls doesn’t seem like a very desirable outcome.

that is the weakest form of nihilism. of course the state of the world has no deeper meaning. of course something will happen.

if you value things, then you have wishes and desires. if you consider people to be responsible for choices, you can assign value to actions and consequences.

some people don’t like devastation of the natural environment. if you understand yourself as part of the world, it feels a lot like self-harm.

In many cases because it’s ugly, or destroys the value of currently valuable property, or gives us unpleasant emotions at the destruction of something we considered beautiful.

It’s natural to want to stop it, same as someone wanting to not have their wallet stolen, or a house they love destroyed and replaced with an apartment complex.

What is recolonization in this context? Does it just mean growth of a new forest?

Well yes and no. If the soil's been sterilised the entire thing needs to be rebuilt from the grasses upwards, forests don't spring up out of nowhere they build up from precursors.

Thanks, I was imagining the smaller stuff as being part of the forest but I suppose maybe the plants that arise first don’t necessarily stick around for the entirety of the forest lifecycle?

Exactly. I don’t remember the exact cycle but basically you first get grass type colonisers, then you might get shrubs, then possibly trees densifying to a forest. Even the tree presence would change as the forest builds up as some essences don’t like being crowded (so won’t replace themselves once the forest densifies) while others prefer shade (so won’t appear until there’s a canopy proper).

It is called "secondary succession" (primary being colonisation from scratch on bare rock)

Perhaps a new forest, but plants in general (current conditions may favor grassland, or something else). It's "re" because there was an ecosystem there before, and now it's returning. Contrast with, say, a brand new island that is the result of volcanic action. Then it'd be just plain old colonization by way of wind-blown seeds, or seeds that survived a bird's digestive tract.

Also frequency. Burning the same area too often will destroy seed banks because the plants cannot reach seed maturity fast enough to rebuild the bank.

Presumably in the meantime its also vulnerable to landslides and then coverage by invasive species of plants.